Positioning-based Framework for Secondary Spectrum Usage J. Nasreddine, O. Sallent, J. P´ erez-Romero, R. Agust´ ı Dept. Signal Theory and Communications (TSC) Universitat Polit` ecnica de Catalunya (UPC) Barcelona, Spain e-mail{jnassred, sallent, jorperez, ramon}@tsc.upc.edu Abstract In this paper, we introduce a framework encompassing the creation and the exploitation of secondary spectrum usage opportunities. The paper de- velops a complete positioning-based framework to assess the feasibility of supporting secondary communications on frequencies which are released by primary spectrum management methodologies. In particular, the paper an- alyzes four possible combinations, depending on known/unknown positions of primary/secondary transceivers. Afterwards, the paper focuses on a spe- cific applicability case, where the dynamic spectrum management mechanism of a WCDMA-based network operator aims at releasing certain frequencies in a large area when possible and thus facilitating secondary exploitation of the released spectrum. Moreover, some practical examples are introduced to show the different procedures when secondary networks with infrastructure are sharing the same frequency with a mobile network. In this context, results have been obtained to assess the practical usability of the released spectrum under different conditions as well as the efficiency of different dynamic spec- trum management methodologies. Keywords - Secondary spectrum use; Cognitive radio; Dynamic spectrum management. 1. Introduction The key purpose of spectrum management techniques is to maximize the value that society gains from the radio spectrum by allowing as many users as possible while ensuring that the interference between different users remains at acceptable levels [1]. Cognitive radios, as devices with the capabilities to be aware of actual transmissions across a wide bandwidth and to adapt their own transmissions to the characteristics of the spectrum, offer great potential of developing advanced spectrum management approaches. Additionally, the pervasive presence of positioning mechanisms in mobile equipments could be very advantageous for novel forms of spectrum management. Adaptive, agile, cognitive radios and networks have unlimited potential to spawn many innovative applications and services that can benefit society as a whole. However, many new technical, business and regulatory challenges need to be addressed to realize such potential.